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x                          CAMEL-LIKE PERISSODACTYLES                     267

three-toed. It was intermediate between a Tapir and a Rhinoceros
in size. It has been shown, too, from casts of the interior of the
skull, that the cerebral hemispheres are much less convoluted than
were those of Titanotherium.

Belated to Palaeosyops is another primitive Titanothere, the
genus TelmatotJierium. This is also Eocene, from the Uinta
Basin, the uppermost of Eocene strata. The skull of these
creatures was rather elongated, and not unlike that of a Titano-
there in general aspect. The dentition was complete and the
canines not very large. The horns, which acquire so prodigious a
development in the later Titanotheres, are just recognisable in at
any rate many species of this genus Tel'matotJieriwrn^ the name
being thus by no means an apt one. Better was that proposed by
Dr. Wortman, of Manteoceras or " prophet horned/* The horns
are small elevations upon the frontals just at the junction of
these with the nasals, and., indeed, lying partly upon the latter
bones. In T. cornutum the horns are chiefly borne upon the very
long nasals., whose size contrasts with the same bones in the
more Mghly- developed Titanotheriu^n. It appears to be quite
possible that TitanotJierium was evolved from the genus

SUB-ORDER 9,    LITOPTERKA.
Whether the MaerancheBiiclae should be considered as a
separate group of Ungulata is a matter of dispute. Cope
placed them in a special order of Ungulates which he called
Iltopterna. Zittel, on the other hand, regards them as definitely
Perissodaetyles. One curious point of resemblance to existing
Horses is shown - that is the presence of a pit in the incisor teeth.
This matter seems to be so important as to need a placing of
these forms in the neighbourhood of the Perissodaetyles, even of
the Equidae ; it is so peculiar a character, and apparently so little
related to any obvious similarity in way of life, that it seems to
mark a special affinity. Not so the fact that in MaeraucJtenia
at any rate the orbit was entirely surrounded by bone as in the
Horse. "We find that condition so frequently acquired in many
groups,  a development from an earlier condition where the cavity
for the lodgment of the eye is in continuity with the temporal
1 See Osbons, Eull. Amer. Mus. XfoL Hist. vii. 1895, p, 82.